The 3rd Generation Partnership Project (3GPP) is currently working to define a comprehensive set of network improvements for Machine-type communication (MTC). Machine-type communication, also known as Machine-to-Machine (M2M) communication, is a form of data communication which involves one or more entities that do not necessarily need human interaction. These entities are referred to as MTC Devices, wherein a MTC Device is a communication device equipped for Machine-type communication and which communicates through a Public Land Mobile Network (PLMN) with one or more MTC Servers and/or one or more other MTC Devices. An MTC Server is a server that communicates with MTC Devices through the PLMN, has an interface which can be accessed by a MTC User, and performs services for the MTC User. The MTC Server also has an interface which can be accessed by a MTC User and performs services for the MTC User. FIG. 1 illustrates schematically a Machine-type communication scenario.
Machine-type communication may be facilitated by the data services offered by existing mobile communication networks. However, a service optimised for machine-type communications differs from a service optimised for human-to-human communications. In particular, machine-type communications are different to current mobile network communication services as they involve different market scenarios, data communications, lower costs and effort, and a potentially very large number of communicating terminals with, to a large extent, little traffic per terminal.
In conventional 3GPP systems, a communication device is allowed to attach to/access a communication network if the device is associated with a subscription that allows the communication network to authenticate the device. For example, the 3GPP Authentication and Key Agreement (AKA) procedure makes use of a globally unique subscriber identity, known as the International Mobile Subscriber Identity (IMSI), which is typically stored on a Universal Subscriber Identity Module (USIM) within a communication device, in order to identify a subscription and thereby authenticate the device. Consequently, an IMSI is typically associated with only one communication device at any one time. However, if each MTC Device were to be associated with a unique subscriber identity (e.g. IMSI), then each MTC Device would need to be individually authenticated using the unique authentication information (e.g. a shared secret key etc) provided in the associated subscription. Due to the very large number of MTC Devices, this individual authentication would generate a large amount of signaling, increasing the load on the network. This would also likely to be a waste of both bandwidth and authentication vectors, especially as it is likely that a proportion of these MTC Devices will not communicate with the network at all. In addition, given that it is likely that there will be a very large number of MTC Devices, if each MTC Device were to be associated with a unique subscriber identity (e.g. IMSI), then the currently defined range of subscriber identities could rapidly be exhausted. Moreover, most MTC Devices will be low power devices that will therefore want to avoid any unnecessary signaling and processing in order to conserve their batteries. This may be particularly important, as it is envisaged that there will be MTC Devices whose batteries will not be changed and that will simply be disposed of when their battery has been drained.
It is therefore desirable to provide an efficient mechanism for authenticating MTC Devices whilst minimizing any modifications that are to be made to the infrastructure provided for subscriber authentication that has already been defined and is currently available in existing communication networks.